The present invention relates to apparatus for cleaning or stripping coated objects, in particular painted or varnished objects, by immersion in a bath of solvent.
There are several methods of stripping painted or varnished objects, one of these being based on pyrolysis, meaning incineration of the varnish layers at temperatures between 500.degree. C. and 700.degree. C. Its disadvantages are a large power consumption, a thermal load inflicted on the objects, difficulties in handling the objects, as well as diffusion of substantial quantities of noxious substances into the atmosphere. Another known method utilises sanding to remove layers of varnish. This method requires comparatively long periods and raises problems regarding removal of the varnish sanding products. Furthermore, the storage of the varnish requires an isolated store. Another known method consists in stripping the varnish by exposing the objects to a jet of high-pressure steam. In this case too, the quantity of energy required is comparatively substantial and a separate store is needed for storage.
Stripping by means of ultrasonics is also known, with the objects which are to be stripped immersed in a solvent bath, which is performed under a normal atmosphere. In this case, the power needed is not as great as in the case of the methods described earlier, but a drawback still persists regarding the environment, deriving from storage of the varnish removed which is still partially charged with solvent. Given that the solvent is inflammable at comparatively low temperatures, there is a very great risk of the solvent bursting into flames or exploding.
Finally, stripping methods in the cold state and in the hot state have been developed, based on processes exploiting special chemical products which for their part give rise to storage problems. Furthermore, the quantities of chemical products required are considerable and the duration of the process is comparatively long.
Consequently, it is an object of the invention to provide apparatus for removing the detachable layers from objects coated therewith, in particular for stripping varnished objects, which despite low operating costs does not produce waste, does not require more than a low consumption of initial material and engenders an emission into the atmosphere which is no more than slight and negligible.